Filter elements, coalescing baffles, filtration vessel and methods

ABSTRACT

Improvements to filtration and vessels such as for filtration and coalescing of gas streams are shown. A filter element with a partial treated region and untreated region such as providing different surface energies or other filtration characteristics are provided. Various keying arrangements for compatibility and/or rotational locking are shown between the filtration vessel, a tubular coalescing baffle, and/or filter element. The tubular coalescing baffle also may include non-louvered pore structure, which provides for more even flow in a two stage type filtration vessel to prevent premature exiting and reduction of flow velocities along the second stage, and/or may additionally or alternatively include drainage apertures such as drain slot formed along a gravitational bottom or otherwise to facilitate additional drainage of coalesced liquid as opposed to letting such liquid be forced through fluid velocity toward the open end of the tubular baffle.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This patent application is a continuation of co-pending U.S. patent application Ser. No. 14/302,606, filed Jun. 12, 2014, which claims the benefit of U.S. Provisional Patent Application No. 61/838,716, filed Jun. 24, 2013, the entire teachings and disclosure of which are incorporated herein by reference thereto.

FIELD OF THE INVENTION

This invention generally relates to filtration vessels, coalescing baffles, and/or filter elements and methods associated with the use.

BACKGROUND OF THE INVENTION

Filtration vessels and coalescers are generally known in the prior art such as shown in U.S. Pat. No. 6,168,647 to Perry Jr. et al.; U.S. Publication Number 2012/0210688 to Burns et al.; U.S. Publication Number 2013/0062273 to Burns et al.; and U.S. Pat. No. 7,108,738 to Burns et al., the entire disclosures of each of these references being incorporated by reference as the different aspects of the present invention may be employed and improvements apply to these prior known filtration vessels and coalescing systems.

Certain aspects are also particularly applicable to a two stage filtration system such as shown in the '647 patent and the '688 publication. These particular types of filtration vessels are known and sold under the name GEMINI available from Peco Facet, a CLARCOR company located in Mineral Wells, Tex. Generally, in these types of systems, a gaseous fluid such as natural gas or other industrial gases are forced through different filter stage elements high pressure allowing for various contaminant removal from the gaseous fluid. Oftentimes, the removal involves removal of oils and other hydrocarbons including crude oil for example, that may be entrained as droplets within the gas stream. It is quite desirable to obtain a high efficiency of removal while satisfying sufficient flow and production rates through the vessel.

Currently, with many of the production sites, there are radical hydrocarbons that are a lot harder to coalesce such as in the fracking regions and certain oil and gas production regions. While GEMINI vessels existing such as covered by the aforementioned '688 and '647 patents or publications provide for a certain amount of filtration and capabilities, further improvements are discussed herein.

BRIEF SUMMARY OF THE INVENTION

In one aspect the present invention provides for a tubular baffle that comprises a tubular extension. A plurality of pores is formed into the tubular extension. At least one drainage aperture is formed into the tubular extension. The tubular extension comprises regions of pores on opposed axial sides of the at least one drainage aperture. Each drainage aperture is larger in flow area than individual ones of the pores.

The at least one drainage aperture can include a plurality of drainage apertures. The tubular extension can include a series of drainage apertures arranged in axial spaced relation. This provides multiple opportunity for liquids to drain and exit the larger drainage apertures.

The tubular baffle may further include a downstream portion comprising the series of drainage slots and an upstream portion at least ⅕ of a length of the tubular extension that is free of the series of drainage apertures.

The porosity of the tubular extension may be between 20% and 40% and further can be between 28% and 35%.

In one embodiment, no louvers cover the pores.

The at least one drainage aperture may intersect and thereby may connect individual pores. However, this feature may also be applied to such louvered applications as in the prior art mentioned in the background.

The at least one drainage aperture can extend at least partially along a gravitational bottom of the tubular baffle as installed in a filtration vessel.

In one embodiment, each drainage aperture may comprise a slot having a length between 1 to 4 inches and a width between ⅛ to ½ inches. The length of each slot may extend circumferentially and the width of each slot may extend axially. For many production/industrial high pressure vessels, the tubular extension can have a diameter of between 3 and 8 inches and a length of at least 1 and ½ feet.

The tubular baffle may have at least one drainage aperture that covers less than ⅓ a circumference of the tubular baffle.

The baffle may further comprise an orientation device orienting the at least one slot at a predetermined gravitational bottom relative to the orientation device.

The tubular extension may comprise first and second open ends and further include a cap portion coupled to one open end. The cap portion can include an end plate with a post projecting from one side and a cup wall with windows projecting from a second opposite side. A porosity of the cup wall via the windows may be at least twice as great as a porosity of the tubular extension. This large flow capacity at the downstream end can encourage axial flow toward the downstream end and axial flow through the element to the downstream end.

The tubular baffle may further include a key arranged at a predetermined orientation relative to the at least one drainage aperture that orients the at least one drainage aperture at a predetermined gravitational bottom relative to the key. In an embodiment, the key may be formed into the post and may comprise an axially extending groove formed into the post.

The tubular baffle and/or a filter element may further include a directional indication formed on the end plate or end cap portion on the second opposite side oriented to indicate the predetermined orientation.

In another aspect the present invention provides for a filtration assembly incorporating such a tubular extension. The filtration assembly may further include a filter element that comprises a ring of filter media with an internal central flow passage. The filter element can have a first portion projecting into and received by the tubular extension and a second portion projecting outside of a first open end of the tubular extension. The filtration assembly may further comprise a coalescing collection chamber formed between the filter element and the tubular extension. The filter element may include a third portion projecting through a second open end of the tubular extension.

Another aspect of the present invention is directed toward a method of coalescing using the filtration assembly. The method may comprise flowing a gas stream through though the filter element having entrained liquid droplets therein. The method further comprises flowing the gas stream radially outward through the ring of filter media while coalescing the entrained liquid droplets along the way. The flow of the flowing gas stream develops moving axially through the coalescing collection chamber and drives the entrained liquid droplets along the tubular extension toward the second open end. The method further includes draining the entrained liquid droplets through the at least one drainage aperture.

The method may include orienting the at least one drainage aperture at a gravitational bottom of the tubular extension and directing the flowing gas stream to flow axially along the first and second portions of the filter element.

In an embodiment, fifty percent to seventy percent of the flowing gas stream may exit from the first portion and thirty percent to fifty percent of the flowing gas stream may exit from the second potion. This can reduce radial flow velocity out through the element and/or baffle by spreading the radial flow over the length of the element more evenly. This reduced flow velocity prevents or reduces the likelihood of re-entraining droplets or atomizing of liquid droplets due to the slower more controlled flow.

A series of drainage apertures may be aligned in axial spaced relation along a region of the tubular extension. As fluid flows along, there are then several opportunities for liquids to drain as opposed to flowing to the end where re-atomization may occur.

In another embodiment the present invention provides for a multiple stage filter element assembly that comprises a filtration vessel that includes a partition dividing the filtration vessel into a first stage and a second stage. There may be at least one opening in the partition. The multiple stage filter element may further include an inlet port in fluid communication with the first stage and an outlet port in fluid communication with the second stage. A filter element (e.g. one or more filter elements) may be disposed in the filtration vessel and extending through the partition. A tubular baffle can surround the filter element. The tubular baffle may comprise a non-louvered perforated extension having a plurality of pores.

Fluid flow in the multiple stage filter element may enter the first stage through the inlet port and pass radially inward through the filter element and along an interior chamber defined within the filter element. It may pass radially outward through the filter element and an intermediate chamber that may be defined between the tubular baffle and the non-louvered perforated extension. Thereafter it may flow to a low pressure chamber surrounding the tubular baffle. The low pressure chamber has a lower pressure than the intermediate chamber during use.

The multiple stage filter element assembly may have a porosity of the non-louvered perforated extension that is between 20% and 40% to provide a more even flow through the filter element over an extension of the filter element within the second stage. It may further have the porosity between 28% and 35%.

Further, the tubular baffle can include drainage apertures. Each drainage aperture may be larger in flow area than individual ones of the pores and may connect individual ones of the pores. In one embodiment, the drainage apertures extend at least partially along a gravitational bottom of the tubular baffle.

The multiple stage filter assembly may have pores that have a pore size of between 0.002 and 0.52 square inches. The pore size may be selected relative to porosity to control radial flow velocities and provide back pressure between the element and the baffle to control such velocities and spread fluid flow more evenly over the length of the filter element.

The non-louvered perforated tubular extension may comprise first and second open ends. There may be a cap portion coupled to one open end. The cap portion may include an end plate with a post projecting from one side and a cup wall with windows projecting from a second opposite side. A porosity of cup wall via the windows may be at least twice as great as a porosity of the non-louvered perforated extension.

The non-louvered perforated extension can extend through the partition. The filter element may have a first portion projecting into and received by the non-louvered perforated extension. It may have a second portion projecting outside of a first open end of the non-louvered perforated extension. A coalescing collection chamber may be formed between the filter element and the non-louvered perforated extension. The filter element may further comprise a third portion that projects through the second open end of the non-louvered perforated extension.

In yet another embodiment or aspect the present invention provides for keying. In one embodiment, a tubular baffle that comprises a tubular extension with a plurality of pores formed into the tubular extension. The tubular extension comprises first and second open ends. A cap portion is coupled to one of the first and second open ends. The cap portion comprises an end plate with a post projecting from one side and a cup wall with windows projecting from a second opposite side. A porosity of the cup wall via the windows are at least twice as great as a porosity of the tubular extension. A key is formed on the cap portion.

In one embodiment, the key may be arranged at a predetermined orientation relative to the tubular extension. For example, the tubular extension may have a bottom portion with a greater drainage capability relative to a remainder of the tubular extension.

The key can be formed into the post. The key may comprise a non-circular keyed structure formed along the post and extending axially. The keyed structure may also comprise an axially extending groove formed into the post.

Further, the post can define a cavity that is formed into the second opposite side for mounting a filter element. The keyed structure can extend into the cavity as a projection from a cylindrical surface of the cavity.

The tubular baffle (or the filter element in an embodiment) may further comprise a directional indication that is formed on the end plate portion on the second opposite side and oriented to indicate the predetermined orientation.

The key may comprise a detent formed at a predetermined angular position relative to a central axis about which the tubular extension surrounds. The post may comprise a tapered tip and a cylindrical body. The key may extend axially into the cylindrical body and the tapered tip.

In yet another embodiment the present invention provides for a multiple stage filter element assembly that comprises a keyed tubular baffle. The multiple stage filter element assembly may further comprise a filtration vessel. A partition divides the filtration vessel into a first stage and a second stage. There is at least one opening in the partition. An inlet port is in fluid communication with the first stage. An outlet port is in fluid communication with the second stage. There is a filter element disposed in the vessel and extending through the partition. The tubular baffle surrounds the filter element and is secured by a support grid. The support grid provides a mounting opening to receive the post and a corresponding key keying with the key. The key may rotationally lock the tubular baffle relative to the filtration vessel and thus provide a predetermined orientation to the tubular baffle.

The multiple stage filtration vessel may further comprise drainage apertures formed along the tubular extension. The key may orient the drainage apertures at a gravitational bottom of the extension to facilitate drainage.

Alternatively or additionally, the key may also key with an end cap of the filter element and rotationally lock the filter element and the tubular baffle. The corresponding key may comprise a tab projecting from a circular surface of the mounting opening.

In still another embodiment the invention provides for a filter element that comprises a ring of filter media with an internal central flow passage. An end cap closes an end of the ring of filter media. The end cap comprises a mounting post and a key is formed along the mounting post.

The mounting post may comprise a circular surface, and further comprise a detent formed into the mounting post that disrupts the circular surface and extends axially along the circular surface.

In one embodiment, the mounting post may comprise an axially extending groove to provide for the key. The mounting post may comprise a tapered tip and a cylindrical body and the key structure may extend axially into the cylindrical body and the tapered tip.

The key may provide means for keying with a tubular baffle having a perforated extension. Without the key, the filter element will not interfit and properly mount with the tubular baffle.

The ring of filter media may extend horizontally along an axis and comprise an upper half on one side of a horizontal plane and intersect the axis and a bottom half on an opposite side of the horizontal plane. The ring of filtration media of the upper half and the bottom half may be different with at least one different filtration, coalescing or flow characteristic.

The key may be positioned at a predetermined position relative to the upper half and bottom half to locate the bottom half at a gravitational bottom when in use. The bottom half of the ring of filter media may comprise a treated region and the upper half may comprise an untreated region. The treated region may comprise a fluorocarbon treatment. The fluorocarbon treatment may include at least one of dipping, aerosol vacuum application, vapor phase adhesion or plasma coating. The treated region can additionally or alternatively comprise an additional media to provide such a different filtering characteristic.

Another aspect of the present invention is directed toward a method of using such a keyed filter element. The method further comprises installing the filter element into a tubular baffle. The tubular baffle can include a tubular extension and a plurality of pores formed into the tubular extension. The method further comprises keying the filter element to the tubular extension. The keying may rotationally lock the filter element to the tubular extension in an embodiment.

The method can further comprise installing the tubular baffle into a support grid in a filtration vessel, keying the tubular baffle to the support grid and rotationally locking the tubular extension to the support grid. The tubular baffle may comprise a post having a cavity receiving the mounting post of the filter element. The cavity may include a circular surface and a radially inward projecting detent.

The key of the filter element can include a clearance void formed into the mounting post to receive the projecting detent. For example, the clearance void can comprise a groove or a flat our other non-round key structure.

In still another embodiment the present invention provides for a filter element that comprises ring of filter media with an internal central flow passage. The filter media includes a treated region and an untreated region. The treated region has a surface energy different than the untreated region with an increased wettability for hydrocarbons.

In one embodiment, the ring of filter media extends horizontally along an axis and comprises an upper half on one side of a horizontal plane intersecting the axis and a bottom half on an opposite side of the horizontal plane. The bottom half comprises the treated region. Greater than 50% of the upper half is free of the treated region.

For orientation of such an embodiment, the filter element may further comprise an orientation device at a predetermined angular orientation relative to the treated region adapted to locate the treated region along a gravitational bottom when installed in a filtration vessel.

The orientation device can include a key formed on an end cap of the filter element. The orientation device can additionally or alternatively include a directional indication marked on the filter element.

The ring of filter media may comprise a tube wound depth media surrounding an axis having a plurality of layers. Alternatively or additionally, the ring of filter media may include a pleated ring portion.

In another embodiment, the ring of filter media may extend horizontally along an axis and include a first stage portion and a second stage portion. The portions may be unitarily formed with each other or separate elements, with a seal element separating the first stage portion from the second stage portion. The treated region extends primarily over the second stage portion.

In a further such embodiment, the treated region may extend only over a portion of the second stage portion. The second stage portion can also include the untreated region. The treated region may be confined to one axial end portion of the second stage portion. A second axial end portion of the second stage portion may be only untreated and form part of the untreated region.

In an embodiment, the first stage portion can be free of the treated region and comprise only the untreated region. The treated region may cover less than half of the second stage portion. The first stage portion and the second stage portion may be formed integrally with each other as a tubular wrap of filter media comprising multiple layers.

The filter element may further comprise a means for keying with a tubular baffle having a perforated extension. Further, it may be that without the means for keying the filter element will not interfit and properly mount with the tubular baffle. The treated region comprises a fluorocarbon treatment.

The fluorocarbon treatment may comprise at least one of dipping, aerosol vacuum application, vapor phase adhesion or plasma coating. Additionally, or alternatively, the treated region may comprise an additional filter media to provide the treated region to modify the surface energy along the treated region.

Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:

FIG. 1 is a side elevational view in partial section of a preferred embodiment of the multi-stage vessel and separator/coalescer filter element of the present invention;

FIG. 2 is a side view of the separator/coalescer filter element of FIG. 1;

FIGS. 2a, 2b, and 2c are similar views to FIG. 2 showing a side elevation view of a separator/coalescer filter element of FIG. 1 according to additional embodiments of the present invention, with FIG. 2a showing an embodiment where the filter media of the filter element includes a treated region on a lower horizontal half and an untreated region on an upper horizontal half of the filter element; FIG. 2b showing a treated region on the second stage portion of the filter element and an untreated region on the first stage of the filter element, and FIG. 2c showing a treated region on a downstream axial end portion of the second stage with untreated regions on an upstream axial end portion of the downstream region and an untreated region as well on the first stage.

FIGS. 2d and 2e are further side elevation views of additional embodiments of the separator and coalescer filter element shown in FIG. 2, but with additional keying system and a treated region on the second stage and lower half in the filter element of FIG. 2d , and a multiple keying system and alternative different key structures being shown in FIG. 2 e.

FIG. 3 is an enlarged view of the chevron-type seal and seal holder of the separator/coalescer filter element of FIG. 2 taken at circle III;

FIG. 4 is a partial cross-sectional view of the chevron-type seal and the seal holder of FIGS. 2 and 3; and

FIG. 5 is a perspective view of the basket cap portion for the flow diffuser basket of the multi-stage vessel of FIG. 1.

FIG. 6 is a side view of the basket cap portion shown in FIG. 5;

FIG. 7 is an axial end view of the basket cap portion shown in FIG. 5;

FIGS. 5a, 6a and 7a are similar figures to those shown in FIGS. 5, 6 and 7 respectively, but showing an alternative embodiment incorporating an additional key system;

FIG. 8 is a side view of an entire assembly of the tubular impingement baffle including the perforated extension and the basket cap portion, which is employed in the filtration vessel illustrated in FIG. 1, with the pore size being exaggerated;

FIG. 9 is an enlarged detail view of the perforated sheet metal plate used in the tubular baffle of FIG. 8 taken about detail A showing the perforated pores better, again with the pore size being enlarged for illustration purposes;

FIG. 10 is a side elevation view of the tubular extension employing drainage apertures, which may be in the form of slots that are sized larger than the pores, the tubular extension being used in the tubular baffle according to the embodiment of FIG. 8;

FIG. 11 is a bottom view showing the gravitational bottom of the tubular extension of FIG. 10.

FIGS. 12-14 are additional views of the basket cap portion used in combination with the perforated tubular extension shown in FIG. 8;

FIG. 15 is an axial end view of the tubular baffle shown in FIG. 8;

FIG. 16 shows a partially schematic and cut away from a bottom view of a filtration vessel incorporating the tubular baffle with slots according to the embodiment of FIG. 8 which schematic may represent that shown in FIG. 1;

FIG. 17 shows an exploded assembly of a downstream support grid including straps carrying aperture, the basket cap portion of the coalescer and filter element end cap, all incorporating a keying system in accordance with an embodiment;

FIGS. 18-20 show perspective, end view and bottom elevation view respectively, of the inlet side end cap for the filter element, that may be used in conjunction at the opposite inlet end with the structure of FIG. 17 being employed at the outlet end; and

FIGS. 21-22 are opposed partially schematic axial end views taken through cross section of a filtration vessel with a filter element and coalescing tubular baffle employing the keying systems shown in FIGS. 17-20.

While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1 of the drawings, the numeral 11 designates the preferred embodiment of a multi-stage vessel for simultaneously filtering solids, separating liquids, pre-coalescing liquids, and coalescing liquids out of a gas stream according to the present invention. This may generally be in accordance with that described in U.S. Pat. No. 6,168,647 to Perry Jr. et al. or U.S. Publication No. 2012/0210688 to Burns et al, or as otherwise incorporated into GEMINI brand filtration vessels available from PECOFacet (US), Inc.

The flow of the gas stream is indicated throughout as arrow G. Multi-stage vessel 11 has a generally tubular hull 12 having an initially open interior. Hull 12 is enclosed on an inlet end 12 a by a conventional closure member 15, preferably a releasable, quick-opening closure. Hull 12 is permanently enclosed on an outlet end 12 b by a cap 13, preferably elliptical. Closure member 15 consists of a conventional head member 16 and a conventional clamping member 17. Head member 16 is releasably sealed to multi-stage vessel 11 by clamping member 17. Clamping member 17 may be released and head member 16 may be opened to allow access to the interior of hull 12. Clamping member 17 provides a fluid-tight seal between hull 12 and head member 16, preferably with a conventional O-ring (not shown). At least one and typically, a plurality of separator/coalescer filter elements 18 are disposed within hull 12, although one element 18 being shown in FIG. 1 to avoid confusion and too busy of drawings. For example, multiple filter elements, tubular baffles and holes in a partition of a two-stage filtration vessel are shown in the '688 publication to Burns.

In that regard, the vessel configuration, separator/coalescer filter elements 18 may generally be any of those filter elements as disclosed in U.S. Pat. No. 6,168,647 to Perry Jr. et al. or U.S. Publication No. 2012/0210688 to Burns et al, both assigned to the present assignee. For example, the filter element 18 may comprise a single continuous filter media tube as in Perry Jr. or a combination or first stage and second stage elements as in various embodiments of Burns et al, that together can form the filter element 18 discussed herein. However as shown in other figures and discussed, the filter element 18 preferably includes a key such as a detent that can key a tubular baffle in an embodiment. The detent may also rotationally lock therewith an embodiment.

Hull 12 is supported by saddle supports 19. A plurality of eyelets 20 are permanently attached to hull 12 to aid in hoisting multi-stage vessel 11 during manufacture, transportation, installation, and maintenance.

The interior of hull 12 is divided into a first stage 21 a and a second stage 21 b by a generally transverse partition 23. Partition 23 includes a plurality of openings 25. Although only a single separator/coalescer filter element 18 and filter guide 27 are shown, it should be understood that openings 25 can be arranged, e.g., in rows on partition 23. In a typical installation, four rows having two to four openings are present. A tubular filter guide 27 is aligned with each opening 25. Each filter guide 27 extends longitudinally a selected distance from partition 23 into first stage 21 a. An inlet port 29 is disposed on hull 12 and opens into first stage 21 a. Inlet port 29 terminates with an inlet flange 31. Inlet flange 31 is adapted to allow multi-stage vessel 11 to be connected to a conventional gas pipeline. Inlet port 29 is located near partition 23 so that as a gas stream flows through inlet port 29 into first stage 21 a, the gas stream impinges upon filter guides 27. In this manner, filter guides 27 aid in the removal of solids and free liquids from the gas stream while protecting separator/coalescer filter elements 18 from erosion. This, as well as other functions of filter guides 27, will be explained in more detail below. An outlet port 33 is disposed on hull 12 and opens into second stage 21 b. Outlet port 33 terminates with an outlet flange 35. Outlet flange 35 is adapted to allow multi-stage vessel 11 to be connected to a conventional gas pipeline. An annular collar 36 is aligned with outlet port 33 and extends into second stage 21 b, thereby creating a barrier and preventing liquids from creeping along the interior surface of second stage 21 band escaping through outlet port 33. Multi-stage vessel 11 is preferably manufactured of steel materials which conform to published pressure-vessel standards, such as ASME Boiler and Pressure Vessel Code, Section 8, Division 1.

Disposed at an underneath portion 12 c of hull 12 is a sump 39 for collecting the filtered solids, the separated liquids, the pre-coalesced liquids, and the coalesced liquids that are removed from the gas stream. Sump 39 is divided into a first-stage sump 39 a and a second-stage sump 39 b by an impermeable sump partition 41. First-stage sump 39 a is generally tubular and is sealed on one end by a first-stage cap 37 a. Typically, first-stage sump 39 a collects separated liquids, pre-coalesced liquids, and solids not filtered by separator/coalescer filter element. Second-stage sump 39 b is generally tubular and is sealed on one end by a second-stage cap 37 b. Typically, second-stage sump 39 b collects coalesced liquids.

A first-stage downcomer 43 a provides fluid communication between first stage 21 a and first-stage sump 39 a. First-stage downcomer 43 a allows drainage of the separated solids, the filtered liquids, and the pre-coalesced liquids from first stage 21 a into first-stage sump 39 a. A second-stage downcomer 43 b provides fluid communication between second stage 21 band second-stage sump 39 b. Second-stage downcomer 43 b allows drainage of the coalesced liquids from second stage 21 b into second-stage sump 39 b. A first-stage sump vent 45 a provides fluid communication between first stage 21 a and first-stage sump 39 a, and acts as a gas vent. First-stage sump vent 45 a allows gas displaced from first-stage sump 39 a to flow back into first stage 21 a. A second-stage sump vent 45 b provides fluid communication between second stage 21 b and second-stage sump 39 b, and acts as a gas vent. Second-stage sump vent 45 b allows gas displaced from second-stage sump 39 b to flow back into second-stage 21 b. A first-stage vent baffle 47 a prevents solids carried by the separated liquids and pre-coalesced liquids from flowing into first-stage sump 39 a. A second-stage vent baffle 47 b prevents mist from flowing back into second stage 21 b from second-stage sump 39 b.

Disposed on the upper side of hull 12 and in fluid communication with first stage 21 a is a first-stage pressure-gauge port 49 a. First-stage pressure-gauge port 49 a is adapted to receive a conventional pressure gauge (not shown) for monitoring the pressure in first-stage 21 a or the differential pressure. Likewise, located on the upper side of hull 12 and in fluid communication with second-stage 21 b is a second-stage pressure gauge port 49 b. Second-stage pressure-gauge port 49 b is adapted to receive a conventional pressure gauge (not shown) for monitoring the pressure in second stage 21 b or the differential pressure.

Continuing with reference to FIG. 1 in the drawings, first-stage gauge glass connections 51 a and 51 b are disposed opposite each other on the upper and lower sides of first-stage sump 39 a and in fluid communication with first-stage sump 39 a. First-stage gauge glass connections 51 a and 51 b are adapted to receive a conventional gauge glass (not shown) for monitoring the level of liquids and solids in first-stage sump 39 a. Similarly, second-stage gauge glass connections 53 a and 53 b are disposed opposite each other on the upper and lower sides of second-stage sump 39 b and in fluid communication with second-stage sump 39 b. Second-stage gauge glass connections 53 a and 53 b are adapted to receive a conventional gauge glass (not shown) for monitoring the level of liquids in second-stage sump 39 b. A plurality of first-stage sump connections 55, preferably operated by valves (not shown), for draining or siphoning solids, liquids, and pre-coalesced liquids out of first-stage sump 39 a, are disposed on first-stage sump 39 a. Similarly, a plurality of second-stage sump connections 57, preferably operated by valves (not shown), for draining or siphoning coalesced liquids and fine liquids out of second-stage sump 39 b, are disposed on second-stage sump 39 b. In addition, first-stage sump connections 55 and second-stage sump connections 57 allow level control instruments and other measuring devices to be inserted into first-stage sump 39 a or second-stage sump 39 b, respectively.

A screen member 61, preferably made of a woven steel material, is disposed in a lower portion 63 of second stage 21 b. Screen member 61 extends substantially the entire length of second stage 21 band acts as a barrier to prevent coalesced liquids that have collected in lower portion 63 from becoming re-entrained in the gas stream.

A grid that may have plurality of first-stage support straps 65 are disposed in first stage 21 a to support separator/coalescer filter elements 18. First-stage support straps 65 generally extend transversely across first stage 21 a, and are connected to the interior of hull 12 by a snap fit or any suitable holding clip member (not shown) that does not require tools to release first-stage support straps 65. It should be understood that one or more first-stage support straps 65 may be connected together, or integrally connected, to form a single webbed network of first-stage support straps 65. First-stage support straps 65 are spatially disposed within first stage 21 a, such that the gas stream may flow unabated around first-stage support straps 65. First-stage support straps 65 include a plurality of apertures 66 to receive separator/coalescer filter elements 18. First-stage support straps 65 are preferably made of rigid material, such as steel or metal. In addition, first-stage support straps 65 hold separator/coalescer filter elements 18 firmly in place, without longitudinal compression, thereby preventing longitudinal movement of separator/coalescer filter elements 18 in backflow situations.

Likewise, a grid comprising a plurality of second-stage support straps 67 are disposed in second stage 21 b to support separator/coalescer filter elements 18. Second-stage support straps 67 generally extend transversely across second stage 21 band are connected to the interior of hull 12. As with first-stage support straps 65, one or more second-stage support straps 67 may be connected together, or integrally connected, to form a single webbed network of second-stage support straps 67. Second-stage support straps 67 are spatially disposed within second stage 21 b such that the gas stream may flow unabated around second-stage support straps 67 toward outlet port 33. Second-stage support straps 67 include a plurality of apertures 68 to receive separator/coalescer filter elements 18 and associated tubular baffles 71.

A plurality of generally basket-shaped tubular baffles 71 are disposed in second stage 21 b to prevent coalesced liquids and fine liquids from becoming re-entrained in the gas stream as the gas stream flows through second stage 21 b toward outlet port 33. A separate tubular baffle 71 is associated with each separator/coalescer filter element 18 and each corresponding opening 25 in partition 23. Tubular baffles 71 are adapted to be inserted through tubular filter guides 27 from first stage 21 a and into second stage 21 b, where tubular baffles 71 are received and carried by second-stage support straps 67. Thus, once installed, tubular baffles 71 extend from second-stage support straps 67, through openings 25, past partition 23, and partially into filter guides 27. Tubular baffles 71 may be removed through filter guides 27 for cleaning, maintenance, and replacement.

Each tubular baffle 71 includes a perforated tubular extension 73 coupled to a basket cap portion 75. It should be understood that perforated tubular extension 73 and basket cap portion 75 may be integrally connected. Perforated tubular extension 73 is adapted to allow the gas stream to flow through, but to prevent coalesced liquids and fine liquids from escaping and becoming re-entrained into the gas stream. In one embodiment, this may accomplished by a plurality of annular louvers (not shown) disposed along the extent of perforated tubular extension 73 such as shown in U.S. Pat. No. 6,168,647. Louvers may be employed with either or both of the keying aspects and/or the drainage slot features. More preferably in one embodiment, a non-louvered perforated extension 73 is employed as shown with a plurality of pores that provide a controlled backpressure.

Tubular baffle 71 with pores and/or drain apertures, along with benefits will be discussed in more detail herein, particularly with respect to FIGS. 8-12 and 16.

Referring now to FIG. 2 in the drawings, a typical separator/coalescer filter element 18 of the present invention is illustrated. Separator/coalescer filter element 18 is preferably a tubular filter element (that may be either cylindrical tube and/or pleated having a filter wall 81 and a hollow core 83. Filter wall 81 of separator/coalescer filter element 18 preferably consists of multi-overlapped layers of non-woven fabric strips, which provide an outer cylindrical surface in one embodiment. The selected density and porosity of separator/coalescer filter elements 18 prevent solids and pre-coalesced liquids from passing through separator/coalescer filter elements 18 and into second stage 21 b of multi-stage vessel 11. Thus, separator/coalescer filter elements 18 are of the same general type as those disclosed in U.S. Pat. No. 5,827,430, issued Oct. 27, 1998 to Perry, Jr., et al, both references of which are incorporated by reference. However, each separator/coalescer filter element 18 of the present invention is circumscribed by an annular seal holder 85. Seal holder 85 is preferably made of polyester and is permanently sealed, or affixed, to filter wall 81. Seal holder 85 is sealingly bonded to filter wall 81 by a heat treatment, but it should be understood that seal holder 85 may be sealed to filter wall by other conventional means, such as glue or adhesive. It is preferable that seal holder 85 does not compress the layers of separator/coalescer filter element 18. Seal holder releasably carries an annular seal 87, preferably a chevron-type seal, as will be explained in more detail below. Other seals and seal arrangements may be employed in other embodiments, as well as alternate filter elements including those disclosed U.S. Publication No. 2012/0210688 to Burns et al. A filter element as used herein may itself comprise two or more end to end elements as shown in Burns et al.

Seal holder 85 and seal 87 separate separator/coalescer filter element 18 into two portions: an inlet portion 89 a (also referred to as first stage portion) and an outlet portion 89 b (also referred to as second stage portion). It is not necessary that inlet portion 89 a and outlet portion 89 b are of the same length. Indeed, depending upon the application, it may be necessary to offset seal holder 85 and seal 87 from the axial center of separator/coalescer filter element 18. It is important to note that both inlet portion 89 b and outlet portion 89 b are of generally homogenous construction and thus integral and continuous; therefore, inlet portion 89 a and outlet portion 89 b are functionally identical in one embodiment, although the lengths of inlet portion 89 a and 89 b may vary. In other embodiments, first and second stage portions are in whole or part functionally different. When seal 87 is a chevron-type seal, inlet portion 89 a and outlet portion 89 b are determined by the orientation of seal 87, as will be explained in more detail below. On the other hand, if seal 87 is an O-ring, or some other type of seal whose functionality is independent of flow direction, then inlet portion 89 a and outlet portion 89 b may be interchangeable. It should be understood that due to differences in the sealing characteristics between a chevron-type seal and an O-ring type seal, the two seals may not be interchangeable for a given separator/coalescer element 18. O-rings or other seals may be employed through in some embodiments.

Inlet portion 89 a terminates with a filter inlet cap 91 a, and outlet portion 89 b terminates with a filter outlet cap 91 b. It is preferable that both filter inlet cap 91 a and filter outlet cap 91 b are identical, but for reasons explained below, filter inlet cap 91 a and filter outlet cap 91 b may be of varying configurations. Filter inlet cap 91 a and filter outlet cap 91 b form a fluid-tight seal with separator/coalescer filter element 18, such that all fluids in the gas stream must pass through filter wall 81. Filter inlet cap 91 a has a filter inlet cap post 93 a that protrudes longitudinally outward from separator/coalescer filter element 18. Filter inlet cap post 93 a preferably tapers inwardly at its outermost extent. In a similar fashion, filter outlet cap 91 b has a filter outlet cap post 93 b that protrudes longitudinally outward from separator/coalescer filter element 18. Filter outlet cap post 93 b preferably tapers inwardly at its outermost extent. Filter inlet cap 91 a and filter outlet cap 91 b are illustrated having a filter inlet cap flange 95 a and a filter outlet cap flange 95 b, respectively, although filter inlet cap 91 a and filter outlet cap 91 b may also be flush with filter wall 81.

Referring to FIG. 3 in the drawings, a blow-up view of circle III of FIG. 2 is illustrated. As mentioned above, inlet portion 89 a and outlet portion 89 b may be functionally identical. When seal 87 is a chevron-type seal, as is preferable, the orientation of seal 87 determines which portion of separator/coalescer filter element 18 represents inlet portion 89 a, and which portion of separator/coalescer filter element 18 represents outlet portion 89 b. Although the orientation of chevron-type seal 87 determines which portion of separator/coalescer filter element 18 represents inlet portion 89 a, it should be understood that other means of ensuring proper installation of separator/coalescer filter element exist. For example, filter inlet cap post 93 a and filter inlet cap post 93 b may be of different sizes or shapes, or filter inlet cap flange 95 a and filter outlet cap flange 95 b may be of different sizes or shapes.

When seal 87 is a chevron-type seal, seal 87 includes a seal base portion 105, a seal vertex portion 107, and a seal cone portion 109. Seal base portion 105 and seal cone portion 107 are integrally joined together at seal vertex portion 107. Seal cone portion 109 is preferably frusto-conical-shaped, having a small-diameter end 111, and a large-diameter end 113. It is preferable that seal base portion 105 and seal cone portion 109 form an angle α of about 60°. In order for seal 87 to operate properly, it is necessary that seal 87 be installed into seal channel 101 such that large-diameter end 113 extends in a direction opposite of the direction of flow of the gas stream. Because large-diameter end 113 extends downward in FIG. 4, the lower end of separator/coalescer filter element 18 becomes inlet portion 89 a, and the upper end of separator/coalescer filter element 18 becomes outlet portion 89 b. Large-diameter end 113 is flexible and can be compressed toward seal base portion 105. Thus, when separator/coalescer filter element 18 is installed into multi-stage vessel 11 (see FIG. 1), large-diameter end 113 is compressed against filter guide 27, thereby forming a fluid-tight seal between first stage 21 a and second stage 21 b. Seal holder 85 and seal 87 allow individual tubular separator/coalescer filter elements 18 to filter solids, separate liquids, and pre-coalesce liquids as the gas stream flows through filter wall 81 of inlet portion 89 a from outside to inside in first stage 21 a, and simultaneously coalesce fluids and fine liquids as the gas stream flows back through filter wall 81 of outlet portion 89 b from inside to outside in second stage 21 b.

Referring now to FIG. 5 in the drawings, basket cap portion 75 of tubular baffle 71 is illustrated in a perspective view. Basket cap portion 75 is generally cup-shaped with a plurality of longitudinal windows 115 spatially arranged around a cylindrical cup wall 117, and which terminate at a plate provided by a flat cup lid 119. A hollow basket cap portion post 121, concentric with cup wall 117 protrudes axially away from cup lid 119. Basket cap portion post terminates at a tapered end 123. Basket cap portion post 123 has a central cavity 125 extending through the plate or lid 119 that is configured to matingly receive filter outlet cap post 93 b, when separator/coalescer filter element 18 is inserted into tubular baffle 71 (see FIG. 1).

Referring back to FIG. 1, and especially FIGS. 8, 9, 10 and 11 in accordance with certain aspects and in one embodiment, the tubular baffle 71 and specifically the tubular extension 73 is shown to include a perforated sheet metal wrap 150 that is free of and does not include louvers, but instead includes perforated pores 152 that are preferably round in one embodiment. Such pores can be punched out in press operations. The sheet metal wrap 150 is formed into a tubular shape and preferably cylindrical and thereby includes opposed ends including an open inlet end 154 and an open outlet end. The open outlet end may be welded or otherwise secured to the rest of the cap portion 75 whereby a large flow windows and openings are provided to facilitate fluid flow.

The perforations can better ensure evenness of the radial flow through the filter element, and/or control the fluid flow and liquid drainage in such a two stage type vessel. In particular, in one embodiment, the first half of the second stage filter media and collection chamber accounts for between about 50-70% of the gas stream exiting through the first half of the second stage filter media, while 30-50% of the gas stream exits the filter media and collections chamber in the second half of the filters second stage. With pores, an intermediate pressure chamber 158 in the form of a cylindrical chamber in one embodiment is formed radially between the outer periphery of the filter element 18 and the inner periphery of the tubular baffle 71. This can provide a backpressure to encourage use of the entire downstream second stage portion of the filter element reducing flow velocity and more controlled axial flow velocity through the baffle.

To achieve the more even flux and benefits and prevent virtually all of the fluid flow from flowing out say the first 3-6 inches of the second stage filter media segment, the pore sizes are tightly controlled, but yet more open than what is provided in the previous louvered baffle situation. Specifically, the porosity of the non-louvered perforated extension is between (“between” meaning including the end ranges) 20% and 40%, and more preferably between 28% and 35%. This porosity measure does not include drain apertures such as slots, which are discussed with association to additional embodiments.

Further, the pores 152 can be smaller in size than louvers as per the prior art, with pore size preferably being between 0.002 and 0.5 square inches in flow area. Preferably, the pores are punched out as round pores having a diameter between 0.05 and 0.2 inch in diameter.

Additionally, or alternatively, drainage apertures 160 are provided along a gravitational bottom 162 of the tubular extension 73. The drainage apertures 160 work in synergy with the pores 152 to facilitate drainage due to the fact that an axial flow of gas and liquids moves axially along the intermediate pressure chamber 158 driving liquids toward the windows or open end proximate the basket cap portion 75. The drain apertures 160 are large enough to facilitate drainage of liquid that is coalesced prior to reaching the end to prevent such liquids from being re-entrained or atomised due to gas flow velocity through the intermediate pressure chamber 158.

The drainage apertures are different than and larger in flow area than individual ones of the pores 152. Further, the drain apertures 160 may intersect (i.e. larger than the spaces between pore) and thereby connect with different ones of the pores 152.

The drainage apertures are located along the gravitational bottom 162 as liquids drains down through gravity or otherwise and are thus located where drainage can be maximized. However, the drainage apertures are not so large as to create unevenness in the flow through the tubular baffle and ensure that the full length of the second stage portion of the filter element 18 is utilized with the goal of maintaining about even radial flow outward from the filter media along the entire length of the filter element in the second stage. The drainage apertures may each have a flow area of between 0.04 and 0.4 square inches, more preferably between 0.1 and 0.4 square inches.

In one embodiment, the drainage apertures comprise a plurality of drain slots that are arranged in a series 164 and axial spaced relation.

Further, tubular baffle may confine the drainage apertures to a downstream portion of the tubular extension 73 to keep higher backpressure at the upstream region and/or for structural integrity to drain liquids where most needed. The downstream portion 166 being shown for example in FIGS. 10, 11 and 16. Further, an upstream portion 168 of the tubular extension 73 is provided that may be free of drainage apertures, with the upstream portion being at least ⅕ the length of the extension. In one embodiment, by restricting the drainage apertures to the downstream portion, this enables liquid to coalesce further along the upstream portion and also maintain their back pressure towards the upstream portion to ensure that more flow through the filter element occurs over the entire length more evenly.

In one embodiment, the drainage apertures are slots that have a length of between 1-4 inches and a width between ⅛ and ½ inches. The slots may extend longitudinally axially, but preferably for strength purposes, the length of each slot extends circumferentially as shown with the width of the drainage slot extending axially. This also allows a greater span of the gravitational bottom. While slots are shown, and are advantageous, other shapes of drainage apertures may be used including simply larger pore openings that are sized substantially larger than those of the pores 152. Again, these would be provided preferably along the gravitational bottom, although some along or around other region are also envisioned.

Additionally, in an embodiment, the drainage slots are spaced axially in the series 164 at least 1 inch apart and more preferably, between 2 and 6 inches apart. This maintains sufficient strength and also maintains sufficient back pressure within the intermediate pressure chamber 158.

Typically, the tubular extension will have a diameter of between 3 inches and 8 inches and a length of at least 1½ feet and typically between 2-4 feet for most embodiments, to provide reference relative to the pore size and drainage aperture arrangements discussed above.

It should be noted that the pores 152 and the drainage apertures 160 may be used in different embodiments independent of each other or in an embodiment combined as shown for example in FIG. 1 and FIGS. 8-11. For example, the slots or other drainage apertures may be added to previous systems such as those shown in U.S. Pat. No. 6,168,674 to Perry Jr. employing a louvered opening arrangement in a baffle, according to one embodiment of the present invention.

While the porosity of the tubular extension is more limited, it is noted that the open end 156 of the tubular extension is not so limited, but opens into the windows formed within the basket cap portion 75 to prevent undue restriction at the far most outlet end of the baffle and filter element so that high flow rates can be ensured as opposed to restricted. The porosity through the windows of the basket cap portion 75 is at least twice as large as the porosity of the tubular extension, and typically at least 85%.

It is also noted that the normal pore size 152 may be between 0.0625 inch in diameter to 0.2 inch in diameter. Drainage aperture 160 would be larger than the pores and in a range of between 0.2 inch and 0.5 inch in diameter, if round.

To orient the gravitational bottom 162 or otherwise to provide for correct compatibility to ensure that the proper baffle is being used or that the proper filter element is being employed, a keying system may be employed. The keying system is shown for example in FIGS. 17-22 and also in FIGS. 5a-7a as well as FIGS. 2d and 2e as it relates to the filter element.

As shown, the apertures 68 in the downstream support grid with straps 67 may include a key 170 in the form of a projecting tab 172 that projects radially inward from the otherwise circular surface of the apertures 68. Inlet grid 65 may or may not have a similar key system that keys with inlet/first stage end caps of the filter element. Also, the tubular baffle 71 along the post 121 may include formed therein a key 174 that is complimentary to key 170. This key 174 may take the form of an annular groove 176 along the outer periphery that extends axially along the post 121 and through the tapered end 123. Additionally, internally, the annular groove 176 becomes a projecting rib 178 that extends axially along the internal cavity 125 of the post 121 such that the key 174 may be provided on one or both the outer periphery surface and inner periphery surface. The key may also be alternatively formed on a different portion of the tubular baffle such as along the plate or cup lid 119, along the cup wall 117 or other such portion. See FIG. 2e as an example with keys 194.

The filter element also includes a complimentary key 180 that mates with the key 174 of the baffle. Key 180 may be formed along the outlet side of post 93 b, and may take the form of a groove 182 that extends axially and through the tapered end in one embodiment.

Each of these keys are arranged at a predetermined orientation relative to the tubular extension 73 and particularly the drainage apertures 160 and gravitational bottom 162 of the tubular extension. Specifically, the keys 170, 174 and 180 are all provided to orient and arrange the drainage slots and at the gravitational bottom during use to facilitate such drainage.

While the projection and groove structure is particularly beneficial and provide for a detent structure to rotationally lock each of the keys 170, 174 and 180 to prevent relative rotation between the tubular baffle and the vessel and prevent relative rotation relative to the filter element and the tubular baffle and/or for compatibility, other such key structures and orientation devices are also contemplated. For example, other detent structures may be employed. In one embodiment, and as shown in FIG. 2e , it may comprise a flat 184 form along the post and/or tabs 186 that are formed at a predetermined angular orientation relative to the post along the end caps of the filter elements. Rather than being tabs, receptacles may alternatively be used along the end caps that would be received or mate with corresponding tabs projecting axially from either the support grids of the vessel and/or the basket cap portion 75 of the tubular baffle 71. Such a keying system may be used additionally for filtration media characteristics to ensure that the proper elements are being in the right or correct vessels. Different filter media grades may be used or different efficiencies needed in different applications for such GEMINI vessels and such a keying system can be used to provide those features.

In the particular arrangement, it has the additional advantage of assisting in installation in that the filter element may be rotationally locked to the tubular baffle and installed together during axial installation to push the tubular baffle 71 into engagement and keying relationship with the support grid 68 and the keyed aperture 68 shown in FIG. 17.

Because the installation is done at the other opposite end, the orientation device may additionally or alternatively include in one embodiment a directional symbol 188 formed upon the inlet end cap 91 a such as an arrow pointing up when oriented correctly. This may be part of the post projection shaped in this format to include a triangular post 190 and a vertical flange 192 vertically below the triangular post. This structure itself may serve as a key 194 and mate with a corresponding keyed aperture receptacle in the inlet support grid straps 65 and openings 66. The advantage of the directional arrow is that it shows the installation which way is up as the installation is largely done blind and the installer can then see which way the filter element needs to be installed to be properly received without difficulty into the tubular baffle 71. Specifically, with reference to FIG. 1 it can be seen that the closure is only at the inlet end and at the other end through the partition wall the outlet side of where the keying structures are provided cannot readily be seen during installation. By providing a directional indication, this assists the service technician in finding the correct keying location. Alternatively, the service technician could operate without such a directional indication by rotating until the corresponding keys are found to facilitate rotational locking and installation.

Additionally, with reference to FIGS. 2a-2d , various embodiments are shown, some of which may benefit from employing a keying structure to facilitate proper orientation of the filter element to arrange a treated region at a predetermined angular orientation with a certain portion of the outer cylindrical periphery of the filter media being located at a gravitational bottom. As mentioned above, the keying system may also be used to simply indicate whether a certain type of filter media or treated filter media may be installed or used and/or to orient the baffle. Any of the keying systems described above may be used in conjunction with these embodiments. Alternatively, it is also possible that the treated media embodiments discussed in FIGS. 2a-2d may also be used along without such keying systems even though synergy exists using those systems together.

Turning then to FIGS. 2a-2d , there is shown a filter element 18 a-18 d, each of which includes a treated region 200 a-200 d, and an untreated region 202 a-202 d. The treated region provides a filtration characteristic that is different than the untreated region. Specifically, the treated region and untreated regions may be along different outer peripheral regions of the filter element. In one embodiment, the treated region has a surface energy that is different than the untreated region with an increased wettability for hydrocarbons. This may be done by way of a fluorocarbon treatment such as plasma fluorination or other chemical additives or coatings along the treated region. The untreated region, however, does not receive such treatment coatings or the like. The untreated region may have greater flow therefore, in some embodiments or a greater porosity. For example, the treated and untreated regions may also include some masking or additional media applied over a certain region.

In the embodiment shown in FIG. 2a , there is provided a filter element 18 a that comprises filter media extending horizontally along the axis to include an upper half 204 and a lower half 206. As shown, the bottom half comprises the treated region 200 a. The lower half may also partially incorporate part of the treated region 200 a in some embodiments. Preferably, the upper half 204 comprises only the untreated region 202 a and does not comprise any portion of the treated region. Preferably, at least half of the upper half is free of such treated region. With this arrangement, the wettability and flow of liquids along the gravitational bottom 208 is enabled or provided. The increased wettability for hydrocarbons facilitates additional flow of liquid through the filter element at these regions. Further, an orientation device such as those previously described including keys for example, may be employed and arranged at predetermined angular orientations to locate the gravitational bottom 208 of the filter element 18 a at the appropriate gravitational bottom location when installed in the filtration vessel and in use.

In the embodiment shown in FIG. 2b , filter element 18 b instead includes a treated region 200 b over the entire second stage 89 b of the filter element downstream of the seal 87. In contrast, the upstream region along the first stage 89 a may be untreated and form the untreated region 202 b in whole or in part. The treated region 202 b may extend partially into the first stage 89 a in this filter element 18 b. This is particularly advantageous when employing a unitary tube for the filter media that extends over both first and second stages 89 a and 89 b whereby the first and second stages are identical but for the additional treatment being formed along the second stage.

Turning then to FIG. 2c , a further embodiment is shown where a filter element 18 c includes a treated region 200 c restricted or confined only to an axial end portion of the second stage 89 b. The second stage 89 b also includes an upstream portion or other axial end portion comprising the untreated region 202 c. The untreated region 202 c may also extend over the first stage 89 a in the filter element 18 c. In this embodiment, the treated region 200 c may also comprise some increased porosity to encourage additional flow toward the end of the filter element to prevent premature exiting of gaseous fluid flow. However, it may also comprise a fluorocarbon treatment to encourage liquid droplet formation at the axial end and closest to the window region 115 of the tubular baffle when employed in use (see other figures).

Turning then to FIG. 2d , yet a further embodiment showing filter element 18 d is shown with a treated region 200 d along the bottom half of the filter element at the gravitational bottom like FIG. 2a , but also restricted primarily to the second stage either substantially or confined as in either of FIGS. 2b and 2c . As shown, the untreated region 220 extends over the first stage in this embodiment. This arrangement and enlarged image also shows the keying system for orientation of gravitational bottom.

All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. 

What is claimed is:
 1. A multiple stage filter element assembly, comprising: a filtration vessel; a partition dividing the filtration vessel into a first stage and a second stage, at least one opening in the partition; an inlet port in fluid communication with the first stage; an outlet port in fluid communication with the second stage; a filter element disposed in the filtration vessel and extending through the partition, a tubular baffle surrounding the filter element, the tubular baffle, comprising: a tubular extension having openings at opposed axial ends; a plurality of pores formed into the tubular extension; at least one drainage aperture, formed into the tubular extension, the tubular extension comprising regions of the pores on opposed axial sides of the at least one drainage aperture, each drainage aperture being larger in flow area than individual ones of the pores, the at least one drainage aperture being arranged along a gravitational bottom of the tubular baffle and spaced from the opposed axial ends, and an orientation device orienting the at least one drainage aperture at the gravitational bottom.
 2. The multiple stage filter element assembly of claim 1, wherein the at least one drainage aperture comprises a plurality of drainage apertures, the tubular extension comprising a series of the drainage apertures arranged in axial spaced relation.
 3. The multiple stage filter element assembly of claim 2, wherein the tubular baffle comprises a downstream portion comprising the series of drainage apertures, and further comprises an upstream portion at least ⅕ of a length of the tubular extension that is free of the series of drainage apertures.
 4. The multiple stage filter element assembly of claim 1, wherein a porosity of the tubular extension is between 20% and 40%.
 5. The multiple stage filter element assembly of claim 4, wherein the porosity is between 28% and 35%, and wherein no louvers cover the pores.
 6. The multiple stage filter element assembly of claim 1, wherein the at least one drainage aperture connects individual pores.
 7. The multiple stage filter element assembly of claim 1, wherein each drainage aperture comprises a slot having a length between 1 to 4 inches and a width between ⅛ to ½ inches, the length of each slot extending circumferentially, the width of each slot extending axially.
 8. The multiple stage filter element assembly of claim 7, wherein the tubular extension has a diameter of between 3 and 8 inches and a length of at least 1 and ½ feet.
 9. The multiple stage filter element assembly of claim 1, wherein the at least one drainage aperture covers less than ⅓ a circumference of the tubular baffle.
 10. The multiple stage filter element assembly of claim 1, wherein the tubular extension comprises first and second open ends, further comprising a cap portion coupled to one open end, the cap portion comprising an end plate with a post projecting from one side, and a cup wall with windows projecting from a second opposite side, a porosity of the cup wall via the windows being at least twice as great as a porosity of the tubular extension.
 11. The multiple stage filter element assembly of claim 10, further comprising a key arranged at a predetermined orientation relative to the at least one drainage aperture orients the at least one drainage aperture at a predetermined gravitational bottom relative to the key.
 12. The multiple stage filter element assembly of claim 11, wherein the key is formed into the post.
 13. The multiple stage filter element assembly of claim 12, wherein the key comprises an axially extending groove formed into the post.
 14. The multiple stage filter element assembly of 12, further comprising a directional indication formed on the end plate portion on the second opposite side oriented to indicate said predetermined orientation.
 15. The multiple stage filter element assembly of claim 1, wherein: the filter element comprises a ring of filter media with an internal central flow passage, the filter element having a first portion projecting into and received by the tubular extension and a second portion projecting outside of a first open end of the tubular extension, further comprising a coalescing collection chamber formed between the filter element and the tubular extension.
 16. The multiple stage filter element assembly of claim 15, wherein the filter element comprises a third portion projecting through a second open end of the tubular extension.
 17. A method of coalescing using the multiple stage filter element assembly of claim 16, comprising: a flowing gas stream through the filter element having entrained liquid droplets therein, flowing the gas stream radially outward through the ring of filter media coalescing the entrained liquid droplets along the way, wherein a flow of the flowing gas stream develops moving axially through the coalescing collection chamber and driving the entrained liquid droplets along the tubular extension toward the second open end, and draining the entrained liquid droplets through the at least one drainage aperture.
 18. The method of claim 17, further comprising orienting the at least one drainage aperture at a gravitational bottom of the tubular extension.
 19. The method of claim 17, further comprising directing the flowing gas stream to flow axially along the first and second portions of the filter element, 50% to 70% of the flowing gas stream exiting from the first portion and 30% to 50% of the flowing gas stream exiting from the second potion.
 20. The method of claim 17, further comprising aligning a series of drainage apertures in axial spaced relation along a region of the tubular extension.
 21. A multiple stage filter element assembly, comprising: a filtration vessel; a partition dividing the filtration vessel into a first stage and a second stage, at least one opening in the partition; an inlet port in fluid communication with the first stage; an outlet port in fluid communication with the second stage; a filter element disposed in the filtration vessel and extending through the partition, a tubular baffle surrounding the filter element, the tubular baffle comprising a perforated extension having a plurality of pores, and at least one drainage aperture formed into the tubular extension, the tubular extension comprising regions of the pores on opposed axial sides of the at least one drainage aperture, each drainage aperture being larger in flow area than individual ones of the pores, the at least one drainage aperture being arranged at a gravitational bottom of the tubular baffle.
 22. The multiple stage filter element assembly of claim 21, wherein fluid flow enters the first stage through the inlet port, passes radially inward through the filter element along an interior chamber defined within the filter element, passes radially outward through the filter element, an intermediate chamber defined between the tubular baffle and the perforated extension, and thereafter to a low pressure chamber surrounding the tubular baffle, the low pressure chamber having a lower pressure than the intermediate chamber during use.
 23. The multiple stage filter element assembly of claim 22, wherein a porosity of the perforated extension is between 20% and 40% to provide a more even flow through the filter element over an extension of the filter element within the second stage.
 24. The multiple stage filter element assembly of claim 23, wherein the porosity is between 28% and 35%.
 25. The multiple stage filter assembly of claim 21, wherein the at least one drainage aperture comprises a plurality of drainage apertures, each drainage aperture being larger in flow area than individual ones of the pores and connecting individual ones of the pores, all of the drainage apertures extending at least partially along a gravitational bottom of the tubular baffle.
 26. The multiple stage filter assembly of claim 25, wherein the drainage apertures comprise slots having a length between 1 to 4 inches and a width between ⅛ to ½ inches, the length of the slots extending circumferentially, the width of the slots extending axially, and wherein the perforated extension has a diameter of between 3 and 8 inches and a length of at least 1 and ½ feet.
 27. The multiple stage filter assembly of claim 25, wherein the drainage apertures cover less than ⅓ a circumference of the tubular baffle, further comprising an orientation device orienting the drainage apertures at the gravitational bottom.
 28. The multiple stage filter assembly of claim 25, wherein the tubular baffle comprises a downstream portion comprising a series of the drainage apertures arranged in axial spaced relation.
 29. The multiple stage filter assembly of claim 28, wherein the tubular baffle further comprises an upstream portion at least ⅕ of a length of the perforated extension that is free of the drainage slots.
 30. The multiple stage filter assembly of claim 21, wherein each of the pores have a pore size of between 0.002 and 0.52 square inches.
 31. The multiple stage filter assembly of claim 21, wherein the perforated tubular extension comprises first and second open ends, further comprising a cap portion coupled to one open end, the cap portion comprising an end plate with a post projecting from one side, and a cup wall with windows projecting from a second opposite side, a porosity of cup wall via the windows being at least twice as great as a porosity of the perforated extension.
 32. The multiple stage filter assembly of claim 21, wherein the perforated extension extends through the partition, and the filter element has a first portion projecting into and received by the perforated extension and a second portion projecting outside of a first open end of the perforated extension, a coalescing collection chamber formed between the filter element and the perforated extension, wherein the filter element comprises a third portion projecting through the second open end of the perforated extension. 